XSS vulnerability in WonderCMS

Vulnerability ID: HTB22759
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_wondercms.html
Product: WonderCMS
Vendor: Robert Isoski ( http://krneky.com/en/wondercms )
Vulnerable Version: 0.3.3 and probably prior versions
Vendor Notification: 21 December 2010
Vulnerability Type: XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
Risk level: Medium
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing (http://www.htbridge.ch/)

Vulnerability Details:
User can execute arbitrary JavaScript code within the vulnerable application.

The vulnerability exists due to failure in the "editText.php" script to properly sanitize user-supplied input in "content" variable. Successful exploitation of this vulnerability could result in a compromise of the application, theft of cookie-based authentication credentials, disclosure or modification of sensitive data.

An attacker can use browser to exploit this vulnerability. The following PoC is available:
http://host/editText.php?fieldname=slogan&content=slogan<img src=x onerror=alert("XSS")>